Power wrench



June 7, 1938. E. H. sHAFF POWER WRENCH Filed March 15, 1935 A l l naif/71% A. @Troma/'S' Patented June 7, 193s UNITED STATES POWER WRENCH Ernest H. Shaff, Grand Haven, Mich., assignor to William H. Keller, Inc., Grand Haven, Mich., a corporation of Michigan Application March 15,

3 claims.

be used for'setting and tightening threaded ele mentsdisposed in places of limited clearance.

Another object is to .provide a power wrench in which aY rotary spindle serves through the medium of smoothly operating Atransmission means to drive with considerable power a flat rotary tool element revolving on a transverse axis beyond the end of the spindle. Another object resides inI the provision o 4means reciprocally moved in a substantially rectilinear path by a rotary cam on a power driven spindle and adapted for rotating a tool socket A substantially 'spaced from the end of the spindle. Another object is to provide a power wrench as aforesaid, characterized by its light weight and ease of manipulation, its simplied arrangement of parts, ease of assembly or replacement, and its generally rugged and durable construction.

Other objects'and advantages will become apparent from the following description and from .the accompanying drawing, in which: Y

'Figure 1 is a transverse sectional view through the tool showing details of construction and showing parts in one operative position.

Fig. 2 is a front elevational view of the tool. Fig.. 3 is a sectional view taken substantially along line 3-3 of Fig. 1. Fig. 4 is a sectional view similar to Fig. 1 but showing the parts in `another operative position. While -the invention is susceptible of various modications and alternative constructions I have shown in the drawing and will herein describe in detail, the preferred embodiment, but it is to be understood that I do not thereby intend to" limit the invention to the specific form disclosed,

but intend to cover all modifications and alternative constructions falling within the spirit and 'scopeof the invention as expressed in the appended claims.

s; transversely disposed relative to the slindle Il.

.In the embodiment of the. invention selected for purposes of illustration, the device includes v apower unit III including-a casing I2 housing.

1935, Serial No. 11,291 (c1. :s1-54) Power lfor rotatably driving the-socket is received from the spindle throughv the medium of a reciprocable pawl,I1 which forms an operating connection. therebetween. n

The spifndlefy `may be rotatably mounted in 5 the usual manner,- the. mounting being provided with friction vreducing means such as a ball bearingl. As here shown, the outer end ofthe; spindleextends beyond the end of Vthe power unit and is vfashioned as a barrel cam I9 including a pair of Iopposite lobes 20. In order to facilitate assembly or detachment, the tool unit I4 may be lremovably secured to the power unit I0. To this end, therefore, the inner end of the tool unit is fashioned as an annular 15 housing 22 providing a chamber 23 and is internally threaded adjacent its edge to be screwed upona threaded'ilange 24 on the power unit. The.chamber 23 is dimensioned to receive the cam I9 with substantial clearance but -occupies only a limited space within the housing, for in order to withstand great strains the housing isA preferably of substantial structure.

Extending axially from the housing is an elongated iiat portion providing the tool carrier of the device which is shown as comprising a nose 25 formed integrally with the housing whichmay be tapered gently toward the base of the nose.

On the nose is secured a pair of similar bearing v plates 21, the nose and plates being suitably 4apertured to receive the shanks of rivets 28 or other suitable fastening means. Preferably the inner ends of the clamping plates are in square abutment with shoulders 29 on the housing 22 at the sides of the nose, so that torsional strains to which the plates may be subjected in operation will not loosen the same The outer ends 30 of the plates 21 project beyond the end of the nosel 25 and are adapted for receiving therebetween tne socket I5. Thus these ends may be coaxially apertured as at 32 and the socket is provided with a hub 33 journaled therein. Medially on the hub is a series of peripheral ratchetteeth' 35 of substantially the same width as the thickness of the'nose I'I and lying between the-ends 30 for deflning the axial position of the socket. In order to insure 1 that the rotary socket I5 will be maintainedstationary against all but driven rotary move ment, means is provided for successively engag-l ing the ratchet teeth 35. Herein this means isv 'shown as a holding vpawl 31 having a rounded base seated within an annular slot Il in the outer` end of the nose 25;""In order to urge the pawl constantly into with the I 'ltdlet teeth; an expansible' springv 39 is seated within a bore 40 and presses the end of the pawl outwardly.

By the present invention, power supplied through the rotary spindle I3 and the cam I9 is transmitted by substantially rectilinear motion of the reciprocal pawl I1 to the socket I5. To the accomplishment of this purpose, the pawl is formed asl an elongated arm disposed to one side of a plane through the axes ofthe spindle and socket. As shown, it is guided in a laterally opening groove or recess 21 Aformed between laterally extending edges of the plates 21. At its inner end it is provided with a follower engageable with the cam. Thus the arm is shaped to form a yoke 42 which is received and guided in an elongated slot 44 in one side of the housing L22. Coaxial apertures -in' the yoke receive a pin 45 which forms the bearing fora roller 41 mounted between the arms and adapted to ride upon the cam I9. At its inner end, the pin 45 extends beyond the yoke into a slot 48 and a spring 49, which is received in an axial bore 50, bears against `the extended end of the pin to urge the same toward Athe end of the spindle t3. Under the influence of the spring, the roller 41 is at all times urged towardthe spindle and thus maintained in contact with theeam I9.

It will be apparent that in the rotation of the spindle il the pawl I1 will be caused to reeiprocate in aA path 'parallel to'the axis of the spindle, the roller 41 following the contour of the cam I9. the -outer end of the pawl, which may be suitably rounded or beveled -to form anv engagement tip 52, successively behind the ratchet teeth 35, thereby rotating the socket by a succession of powerful thrusts. Satisfactory results have been obtained in practice by reciprocating the pawl |1.rapidly enough to cause the socket to rotate at about 200 revolutions per minute.

In the course'of moving the tool ratchet. the tip 52 is caused to`follow a slight arc following the rotary movement of the socket. In order to engage a succeeding tooth, therefore, the tip 52 must be moved laterally inwardly as an incident to reciprocation of the pawl. Accordingly, a rocking motion is imparted to the pawl arm so as to carry its tip 52 inwardly or in a direction toward the axis of the nose 25. As shown, the pawl is maintained in spaced relation tothe adjoining edge of the nose 25, and the roller 41 is adapted to fulcrum on the cam I9 under the pressure of the spring 49 on the offset end -of the pin 45. Thus in the retracting movement of the pawl, the spring 50 acts to swing the tip into position to engage a succeeding ratchet tooth.

It will be observed that the pawl I1 and the cam follower carried thereby constitute a floating unit guided by the groove or recess 21L and slot 44 and capable of easy removal. To retain it inl position I provide a cover plate 54 which is'secured over the slot 44 as by means of screws 55, and has a retaining gide finger 58 extending overthepawl.

In operation, the operator places the rotary, socket l5, or an adapter socket such as is .commonly employed for the purpose,linfengage ment with the threaded element to be secured and turns on the power to rotate the spindle I3.

Thereupon the cam IS causes the pawl l1 to reciprocate rapidly and thus rotate the socket I5 n,

until the threaded element has been set. desired,thepowermeansmaybeofthetype This reciprocatory movement carries arranged to stall after the threaded element has been set with predetermined pressure. However,

it isusually desirable to tighten the threaded element thoroughly in excess of the force the power means of the tool is adapted to furnish, `and to this end the device is arranged so that manual force for tightening a threaded element may be exerted by moving the tool in the direction of rotation of the socket I5, the pawl 31 holding the socket stationary relative to the tool in the meanwhile. It is thus apparent that not only is the tool capable of rapidly setting the threaded element through power driven means, but it may also be used for manually tightening the element.

A further valuable feature of the present invention resides in the fact that in addition to its use for setting and tightening a threaded element, the tool may also be'used ior removing such an element. .'I'he latter end is attained by turning the flat tool unit over to reverse the position. of

the ratchet socket upon the threaded element vmanual force being available as desired to initially loosen the element.

It will thus be apparent that the present inbodies few and simple parts which may be as- 30 sembled speedily andwith ease, and the construction is eicient in use and of durable construction. Moreover, the present tool embodies advantages such as reversibility for either setting or removing a threaded element, and while the tool may be side operating in that the axisof the driving socket is transversely arranged relative to the axis of the toolbodyfpower is supplied by any suitable economical rotary moto means. i

I claim as my invention:

1. In comb-ination in a power driven tool of the character described, a body housing rotary parts including a spindle, a narrow-wall barrel cam on the end of said spindle, means including an elongated flat tool portion providing an extension of said body and carrying a toothed rotary ratchet socket for engaging a threaded element to be land including an oilst part adjacent'and to oney side of the follower, and resilient means bearing against said offset part for causing said follower to fulcrum on said cam and rock said arm incident fo rectilinear movement thereof.A

2. A power wrench comprising, in combination,A

a power unit including a spindle and means for rotating said spindle,v a tool unit secured to said power unit and extending substantially beyond.

the end of said spindle, an'elongated fiat portion on the outer end of said tool unit. a toothed ro' tary ratchet socket supported by said ilat portion, a reciprocatory pawl arm disposed .along one margin of said flat portion in engagementl at one `end with said ratchet socket andhaving a follower coacting with its opposite end, cam means upon the end of said spindle and cooperatively moving said arm in a reciprocatory path upon roarranged in engagement Ywith said'follower for ing means of substantial body, said spacing means lhaving a generally longitudinally disposed bore tation of said spindle, an oilset part carried by said arm adjacent said follower and extending toward the axis of said fiat portion, and means centrally disposed within. said at portion for resiliently urging saidoilset part toward said cam means, whereby to overbalance said arm and carry said one end thereof toward the axis of said flat portion so as'to move the same positively into engagement with successive teeth of said ratchet socket. 9

3. In combination, in a wrench construction of the character described,'a hollow housing having driving means therein and a nose portion projecting therefrom, said nose portion including a pair of at plates having therebetween flat spacopening toward the interior of said housing, a toothed rotary socket carried between the front ends of said spacing means, a pawl arm extending from said driving means to be moved thereby in a. rectilinear path and engageable with the teeth of said socket for advancing the same rotatably, means projecting laterally from said arm between the opening of s'aid bore and the interior of the housing, and compression means within said bore coacting with said laterally projecting 

